drivers/usb/misc/onboard_usb_hub.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * Driver for onboard USB hubs
  *
  * Copyright (c) 2022, Google LLC
  */

 #include <linux/clk.h>
 #include <linux/device.h>
 #include <linux/export.h>
 #include <linux/err.h>
 #include <linux/gpio/consumer.h>
 #include <linux/init.h>
 #include <linux/kernel.h>
 #include <linux/list.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
 #include <linux/of.h>
 #include <linux/of_platform.h>
 #include <linux/platform_device.h>
 #include <linux/regulator/consumer.h>
 #include <linux/slab.h>
 #include <linux/suspend.h>
 #include <linux/sysfs.h>
 #include <linux/usb.h>
 #include <linux/usb/hcd.h>
 #include <linux/usb/onboard_hub.h>
 #include <linux/workqueue.h>

 #include "onboard_usb_hub.h"

 /*
  * Use generic names, as the actual names might differ between hubs. If a new
  * hub requires more than the currently supported supplies, add a new one here.
  */
 static const char * const supply_names[] = {
 	"vdd",
 	"vdd2",
 };

 #define MAX_SUPPLIES ARRAY_SIZE(supply_names)

 static void onboard_hub_attach_usb_driver(struct work_struct *work);

 static struct usb_device_driver onboard_hub_usbdev_driver;
 static DECLARE_WORK(attach_usb_driver_work, onboard_hub_attach_usb_driver);

 /************************** Platform driver **************************/

 struct usbdev_node {
 	struct usb_device *udev;
 	struct list_head list;
 };

 struct onboard_hub {
 	struct regulator_bulk_data supplies[MAX_SUPPLIES];
 	struct device *dev;
 	const struct onboard_hub_pdata *pdata;
 	struct gpio_desc *reset_gpio;
 	bool always_powered_in_suspend;
 	bool is_powered_on;
 	bool going_away;
 	struct list_head udev_list;
 	struct mutex lock;
 	struct clk *clk;
 };

 static int onboard_hub_power_on(struct onboard_hub *hub)
 {
 	int err;

 	err = clk_prepare_enable(hub->clk);
 	if (err) {
 		dev_err(hub->dev, "failed to enable clock: %pe\n", ERR_PTR(err));
 		return err;
 	}

 	err = regulator_bulk_enable(hub->pdata->num_supplies, hub->supplies);
 	if (err) {
 		dev_err(hub->dev, "failed to enable supplies: %pe\n", ERR_PTR(err));
 		return err;
 	}

 	fsleep(hub->pdata->reset_us);
 	gpiod_set_value_cansleep(hub->reset_gpio, 0);

 	hub->is_powered_on = true;

 	return 0;
 }

 static int onboard_hub_power_off(struct onboard_hub *hub)
 {
 	int err;

 	gpiod_set_value_cansleep(hub->reset_gpio, 1);

 	err = regulator_bulk_disable(hub->pdata->num_supplies, hub->supplies);
 	if (err) {
 		dev_err(hub->dev, "failed to disable supplies: %pe\n", ERR_PTR(err));
 		return err;
 	}

 	clk_disable_unprepare(hub->clk);

 	hub->is_powered_on = false;

 	return 0;
 }

 static int __maybe_unused onboard_hub_suspend(struct device *dev)
 {
 	struct onboard_hub *hub = dev_get_drvdata(dev);
 	struct usbdev_node *node;
 	bool power_off = true;

 	if (hub->always_powered_in_suspend)
 		return 0;

 	mutex_lock(&hub->lock);

 	list_for_each_entry(node, &hub->udev_list, list) {
 		if (!device_may_wakeup(node->udev->bus->controller))
 			continue;

 		if (usb_wakeup_enabled_descendants(node->udev)) {
 			power_off = false;
 			break;
 		}
 	}

 	mutex_unlock(&hub->lock);

 	if (!power_off)
 		return 0;

 	return onboard_hub_power_off(hub);
 }

 static int __maybe_unused onboard_hub_resume(struct device *dev)
 {
 	struct onboard_hub *hub = dev_get_drvdata(dev);

 	if (hub->is_powered_on)
 		return 0;

 	return onboard_hub_power_on(hub);
 }

 static inline void get_udev_link_name(const struct usb_device *udev, char *buf, size_t size)
 {
 	snprintf(buf, size, "usb_dev.%s", dev_name(&udev->dev));
 }

 static int onboard_hub_add_usbdev(struct onboard_hub *hub, struct usb_device *udev)
 {
 	struct usbdev_node *node;
 	char link_name[64];
 	int err;

 	mutex_lock(&hub->lock);

 	if (hub->going_away) {
 		err = -EINVAL;
 		goto error;
 	}

 	node = kzalloc(sizeof(*node), GFP_KERNEL);
 	if (!node) {
 		err = -ENOMEM;
 		goto error;
 	}

 	node->udev = udev;

 	list_add(&node->list, &hub->udev_list);

 	mutex_unlock(&hub->lock);

 	get_udev_link_name(udev, link_name, sizeof(link_name));
 	WARN_ON(sysfs_create_link(&hub->dev->kobj, &udev->dev.kobj, link_name));

 	return 0;

 error:
 	mutex_unlock(&hub->lock);

 	return err;
 }

 static void onboard_hub_remove_usbdev(struct onboard_hub *hub, const struct usb_device *udev)
 {
 	struct usbdev_node *node;
 	char link_name[64];

 	get_udev_link_name(udev, link_name, sizeof(link_name));
 	sysfs_remove_link(&hub->dev->kobj, link_name);

 	mutex_lock(&hub->lock);

 	list_for_each_entry(node, &hub->udev_list, list) {
 		if (node->udev == udev) {
 			list_del(&node->list);
 			kfree(node);
 			break;
 		}
 	}

 	mutex_unlock(&hub->lock);
 }

 static ssize_t always_powered_in_suspend_show(struct device *dev, struct device_attribute *attr,
 			   char *buf)
 {
 	const struct onboard_hub *hub = dev_get_drvdata(dev);

 	return sysfs_emit(buf, "%d\n", hub->always_powered_in_suspend);
 }

 static ssize_t always_powered_in_suspend_store(struct device *dev, struct device_attribute *attr,
 			    const char *buf, size_t count)
 {
 	struct onboard_hub *hub = dev_get_drvdata(dev);
 	bool val;
 	int ret;

 	ret = kstrtobool(buf, &val);
 	if (ret < 0)
 		return ret;

 	hub->always_powered_in_suspend = val;

 	return count;
 }
 static DEVICE_ATTR_RW(always_powered_in_suspend);

 static struct attribute *onboard_hub_attrs[] = {
 	&dev_attr_always_powered_in_suspend.attr,
 	NULL,
 };
 ATTRIBUTE_GROUPS(onboard_hub);

 static void onboard_hub_attach_usb_driver(struct work_struct *work)
 {
 	int err;

 	err = driver_attach(&onboard_hub_usbdev_driver.driver);
 	if (err)
 		pr_err("Failed to attach USB driver: %pe\n", ERR_PTR(err));
 }

 static int onboard_hub_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	struct onboard_hub *hub;
 	unsigned int i;
 	int err;

 	hub = devm_kzalloc(dev, sizeof(*hub), GFP_KERNEL);
 	if (!hub)
 		return -ENOMEM;

 	hub->pdata = device_get_match_data(&pdev->dev);
 	if (!hub->pdata)
 		return -EINVAL;

 	if (hub->pdata->num_supplies > MAX_SUPPLIES)
 		return dev_err_probe(dev, -EINVAL, "max %zu supplies supported!\n",
 				     MAX_SUPPLIES);

 	for (i = 0; i < hub->pdata->num_supplies; i++)
 		hub->supplies[i].supply = supply_names[i];

 	err = devm_regulator_bulk_get(dev, hub->pdata->num_supplies, hub->supplies);
 	if (err) {
 		dev_err(dev, "Failed to get regulator supplies: %pe\n", ERR_PTR(err));
 		return err;
 	}

 	hub->clk = devm_clk_get_optional(dev, NULL);
 	if (IS_ERR(hub->clk))
 		return dev_err_probe(dev, PTR_ERR(hub->clk), "failed to get clock\n");

 	hub->reset_gpio = devm_gpiod_get_optional(dev, "reset",
 						  GPIOD_OUT_HIGH);
 	if (IS_ERR(hub->reset_gpio))
 		return dev_err_probe(dev, PTR_ERR(hub->reset_gpio), "failed to get reset GPIO\n");

 	hub->dev = dev;
 	mutex_init(&hub->lock);
 	INIT_LIST_HEAD(&hub->udev_list);

 	dev_set_drvdata(dev, hub);

 	err = onboard_hub_power_on(hub);
 	if (err)
 		return err;

 	/*
 	 * The USB driver might have been detached from the USB devices by
 	 * onboard_hub_remove() (e.g. through an 'unbind' by userspace),
 	 * make sure to re-attach it if needed.
 	 *
 	 * This needs to be done deferred to avoid self-deadlocks on systems
 	 * with nested onboard hubs.
 	 */
 	schedule_work(&attach_usb_driver_work);

 	return 0;
 }

 static void onboard_hub_remove(struct platform_device *pdev)
 {
 	struct onboard_hub *hub = dev_get_drvdata(&pdev->dev);
 	struct usbdev_node *node;
 	struct usb_device *udev;

 	hub->going_away = true;

 	mutex_lock(&hub->lock);

 	/* unbind the USB devices to avoid dangling references to this device */
 	while (!list_empty(&hub->udev_list)) {
 		node = list_first_entry(&hub->udev_list, struct usbdev_node, list);
 		udev = node->udev;

 		/*
 		 * Unbinding the driver will call onboard_hub_remove_usbdev(),
 		 * which acquires hub->lock.  We must release the lock first.
 		 */
 		get_device(&udev->dev);
 		mutex_unlock(&hub->lock);
 		device_release_driver(&udev->dev);
 		put_device(&udev->dev);
 		mutex_lock(&hub->lock);
 	}

 	mutex_unlock(&hub->lock);

 	onboard_hub_power_off(hub);
 }

 MODULE_DEVICE_TABLE(of, onboard_hub_match);

 static const struct dev_pm_ops __maybe_unused onboard_hub_pm_ops = {
 	SET_LATE_SYSTEM_SLEEP_PM_OPS(onboard_hub_suspend, onboard_hub_resume)
 };

 static struct platform_driver onboard_hub_driver = {
 	.probe = onboard_hub_probe,
 	.remove_new = onboard_hub_remove,

 	.driver = {
 		.name = "onboard-usb-hub",
 		.of_match_table = onboard_hub_match,
 		.pm = pm_ptr(&onboard_hub_pm_ops),
 		.dev_groups = onboard_hub_groups,
 	},
 };

 /************************** USB driver **************************/

 #define VENDOR_ID_CYPRESS	0x04b4
 #define VENDOR_ID_GENESYS	0x05e3
 #define VENDOR_ID_MICROCHIP	0x0424
 #define VENDOR_ID_REALTEK	0x0bda
 #define VENDOR_ID_TI		0x0451
 #define VENDOR_ID_VIA		0x2109

 /*
  * Returns the onboard_hub platform device that is associated with the USB
  * device passed as parameter.
  */
 static struct onboard_hub *_find_onboard_hub(struct device *dev)
 {
 	struct platform_device *pdev;
 	struct device_node *np;
 	struct onboard_hub *hub;

 	pdev = of_find_device_by_node(dev->of_node);
 	if (!pdev) {
 		np = of_parse_phandle(dev->of_node, "peer-hub", 0);
 		if (!np) {
 			dev_err(dev, "failed to find device node for peer hub\n");
 			return ERR_PTR(-EINVAL);
 		}

 		pdev = of_find_device_by_node(np);
 		of_node_put(np);

 		if (!pdev)
 			return ERR_PTR(-ENODEV);
 	}

 	hub = dev_get_drvdata(&pdev->dev);
 	put_device(&pdev->dev);

 	/*
 	 * The presence of drvdata ('hub') indicates that the platform driver
 	 * finished probing. This handles the case where (conceivably) we could
 	 * be running at the exact same time as the platform driver's probe. If
 	 * we detect the race we request probe deferral and we'll come back and
 	 * try again.
 	 */
 	if (!hub)
 		return ERR_PTR(-EPROBE_DEFER);

 	return hub;
 }

 static int onboard_hub_usbdev_probe(struct usb_device *udev)
 {
 	struct device *dev = &udev->dev;
 	struct onboard_hub *hub;
 	int err;

 	/* ignore supported hubs without device tree node */
 	if (!dev->of_node)
 		return -ENODEV;

 	hub = _find_onboard_hub(dev);
 	if (IS_ERR(hub))
 		return PTR_ERR(hub);

 	dev_set_drvdata(dev, hub);

 	err = onboard_hub_add_usbdev(hub, udev);
 	if (err)
 		return err;

 	return 0;
 }

 static void onboard_hub_usbdev_disconnect(struct usb_device *udev)
 {
 	struct onboard_hub *hub = dev_get_drvdata(&udev->dev);

 	onboard_hub_remove_usbdev(hub, udev);
 }

 static const struct usb_device_id onboard_hub_id_table[] = {
 	{ USB_DEVICE(VENDOR_ID_CYPRESS, 0x6504) }, /* CYUSB33{0,1,2}x/CYUSB230x 3.0 */
 	{ USB_DEVICE(VENDOR_ID_CYPRESS, 0x6506) }, /* CYUSB33{0,1,2}x/CYUSB230x 2.0 */
 	{ USB_DEVICE(VENDOR_ID_CYPRESS, 0x6570) }, /* CY7C6563x 2.0 */
 	{ USB_DEVICE(VENDOR_ID_GENESYS, 0x0608) }, /* Genesys Logic GL850G USB 2.0 */
 	{ USB_DEVICE(VENDOR_ID_GENESYS, 0x0610) }, /* Genesys Logic GL852G USB 2.0 */
 	{ USB_DEVICE(VENDOR_ID_GENESYS, 0x0620) }, /* Genesys Logic GL3523 USB 3.1 */
 	{ USB_DEVICE(VENDOR_ID_MICROCHIP, 0x2412) }, /* USB2412 USB 2.0 */
 	{ USB_DEVICE(VENDOR_ID_MICROCHIP, 0x2514) }, /* USB2514B USB 2.0 */
 	{ USB_DEVICE(VENDOR_ID_MICROCHIP, 0x2517) }, /* USB2517 USB 2.0 */
 	{ USB_DEVICE(VENDOR_ID_MICROCHIP, 0x2744) }, /* USB5744 USB 2.0 */
 	{ USB_DEVICE(VENDOR_ID_MICROCHIP, 0x5744) }, /* USB5744 USB 3.0 */
 	{ USB_DEVICE(VENDOR_ID_REALTEK, 0x0411) }, /* RTS5411 USB 3.1 */
 	{ USB_DEVICE(VENDOR_ID_REALTEK, 0x5411) }, /* RTS5411 USB 2.1 */
 	{ USB_DEVICE(VENDOR_ID_REALTEK, 0x0414) }, /* RTS5414 USB 3.2 */
 	{ USB_DEVICE(VENDOR_ID_REALTEK, 0x5414) }, /* RTS5414 USB 2.1 */
 	{ USB_DEVICE(VENDOR_ID_TI, 0x8140) }, /* TI USB8041 3.0 */
 	{ USB_DEVICE(VENDOR_ID_TI, 0x8142) }, /* TI USB8041 2.0 */
 	{ USB_DEVICE(VENDOR_ID_VIA, 0x0817) }, /* VIA VL817 3.1 */
 	{ USB_DEVICE(VENDOR_ID_VIA, 0x2817) }, /* VIA VL817 2.0 */
 	{}
 };
 MODULE_DEVICE_TABLE(usb, onboard_hub_id_table);

 static struct usb_device_driver onboard_hub_usbdev_driver = {
 	.name = "onboard-usb-hub",
 	.probe = onboard_hub_usbdev_probe,
 	.disconnect = onboard_hub_usbdev_disconnect,
 	.generic_subclass = 1,
 	.supports_autosuspend =	1,
 	.id_table = onboard_hub_id_table,
 };

 static int __init onboard_hub_init(void)
 {
 	int ret;

 	ret = usb_register_device_driver(&onboard_hub_usbdev_driver, THIS_MODULE);
 	if (ret)
 		return ret;

 	ret = platform_driver_register(&onboard_hub_driver);
 	if (ret)
 		usb_deregister_device_driver(&onboard_hub_usbdev_driver);

 	return ret;
 }
 module_init(onboard_hub_init);

 static void __exit onboard_hub_exit(void)
 {
 	usb_deregister_device_driver(&onboard_hub_usbdev_driver);
 	platform_driver_unregister(&onboard_hub_driver);

 	cancel_work_sync(&attach_usb_driver_work);
 }
 module_exit(onboard_hub_exit);

 MODULE_AUTHOR("Matthias Kaehlcke <mka@chromium.org>");
 MODULE_DESCRIPTION("Driver for discrete onboard USB hubs");
 MODULE_LICENSE("GPL v2");
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* Driver for onboard USB hubs
	*
	* Copyright (c) 2022, Google LLC
	*/

	#include <linux/clk.h>
	#include <linux/device.h>
	#include <linux/export.h>
	#include <linux/err.h>
	#include <linux/gpio/consumer.h>
	#include <linux/init.h>
	#include <linux/kernel.h>
	#include <linux/list.h>
	#include <linux/module.h>
	#include <linux/mutex.h>
	#include <linux/of.h>
	#include <linux/of_platform.h>
	#include <linux/platform_device.h>
	#include <linux/regulator/consumer.h>
	#include <linux/slab.h>
	#include <linux/suspend.h>
	#include <linux/sysfs.h>
	#include <linux/usb.h>
	#include <linux/usb/hcd.h>
	#include <linux/usb/onboard_hub.h>
	#include <linux/workqueue.h>

	#include "onboard_usb_hub.h"

	/*
	* Use generic names, as the actual names might differ between hubs. If a new
	* hub requires more than the currently supported supplies, add a new one here.
	*/
	static const char * const supply_names[] = {
	"vdd",
	"vdd2",
	};

	#define MAX_SUPPLIES ARRAY_SIZE(supply_names)

	static void onboard_hub_attach_usb_driver(struct work_struct *work);

	static struct usb_device_driver onboard_hub_usbdev_driver;
	static DECLARE_WORK(attach_usb_driver_work, onboard_hub_attach_usb_driver);

	/************************ Platform driver ************************/

	struct usbdev_node {
	struct usb_device *udev;
	struct list_head list;
	};

	struct onboard_hub {
	struct regulator_bulk_data supplies[MAX_SUPPLIES];
	struct device *dev;
	const struct onboard_hub_pdata *pdata;
	struct gpio_desc *reset_gpio;
	bool always_powered_in_suspend;
	bool is_powered_on;
	bool going_away;
	struct list_head udev_list;
	struct mutex lock;
	struct clk *clk;
	};

	static int onboard_hub_power_on(struct onboard_hub *hub)
	{
	int err;

	err = clk_prepare_enable(hub->clk);
	if (err) {
	dev_err(hub->dev, "failed to enable clock: %pe\n", ERR_PTR(err));
	return err;
	}

	err = regulator_bulk_enable(hub->pdata->num_supplies, hub->supplies);
	if (err) {
	dev_err(hub->dev, "failed to enable supplies: %pe\n", ERR_PTR(err));
	return err;
	}

	fsleep(hub->pdata->reset_us);
	gpiod_set_value_cansleep(hub->reset_gpio, 0);

	hub->is_powered_on = true;

	return 0;
	}

	static int onboard_hub_power_off(struct onboard_hub *hub)
	{
	int err;

	gpiod_set_value_cansleep(hub->reset_gpio, 1);

	err = regulator_bulk_disable(hub->pdata->num_supplies, hub->supplies);
	if (err) {
	dev_err(hub->dev, "failed to disable supplies: %pe\n", ERR_PTR(err));
	return err;
	}

	clk_disable_unprepare(hub->clk);

	hub->is_powered_on = false;

	return 0;
	}

	static int __maybe_unused onboard_hub_suspend(struct device *dev)
	{
	struct onboard_hub *hub = dev_get_drvdata(dev);
	struct usbdev_node *node;
	bool power_off = true;

	if (hub->always_powered_in_suspend)
	return 0;

	mutex_lock(&hub->lock);

	list_for_each_entry(node, &hub->udev_list, list) {
	if (!device_may_wakeup(node->udev->bus->controller))
	continue;

	if (usb_wakeup_enabled_descendants(node->udev)) {
	power_off = false;
	break;
	}
	}

	mutex_unlock(&hub->lock);

	if (!power_off)
	return 0;

	return onboard_hub_power_off(hub);
	}

	static int __maybe_unused onboard_hub_resume(struct device *dev)
	{
	struct onboard_hub *hub = dev_get_drvdata(dev);

	if (hub->is_powered_on)
	return 0;

	return onboard_hub_power_on(hub);
	}

	static inline void get_udev_link_name(const struct usb_device udev, char buf, size_t size)
	{
	snprintf(buf, size, "usb_dev.%s", dev_name(&udev->dev));
	}

	static int onboard_hub_add_usbdev(struct onboard_hub hub, struct usb_device udev)
	{
	struct usbdev_node *node;
	char link_name[64];
	int err;

	mutex_lock(&hub->lock);

	if (hub->going_away) {
	err = -EINVAL;
	goto error;
	}

	node = kzalloc(sizeof(*node), GFP_KERNEL);
	if (!node) {
	err = -ENOMEM;
	goto error;
	}

	node->udev = udev;

	list_add(&node->list, &hub->udev_list);

	mutex_unlock(&hub->lock);

	get_udev_link_name(udev, link_name, sizeof(link_name));
	WARN_ON(sysfs_create_link(&hub->dev->kobj, &udev->dev.kobj, link_name));

	return 0;

	error:
	mutex_unlock(&hub->lock);

	return err;
	}

	static void onboard_hub_remove_usbdev(struct onboard_hub hub, const struct usb_device udev)
	{
	struct usbdev_node *node;
	char link_name[64];

	get_udev_link_name(udev, link_name, sizeof(link_name));
	sysfs_remove_link(&hub->dev->kobj, link_name);

	mutex_lock(&hub->lock);

	list_for_each_entry(node, &hub->udev_list, list) {
	if (node->udev == udev) {
	list_del(&node->list);
	kfree(node);
	break;
	}
	}

	mutex_unlock(&hub->lock);
	}

	static ssize_t always_powered_in_suspend_show(struct device dev, struct device_attribute attr,
	char *buf)
	{
	const struct onboard_hub *hub = dev_get_drvdata(dev);

	return sysfs_emit(buf, "%d\n", hub->always_powered_in_suspend);
	}

	static ssize_t always_powered_in_suspend_store(struct device dev, struct device_attribute attr,
	const char *buf, size_t count)
	{
	struct onboard_hub *hub = dev_get_drvdata(dev);
	bool val;
	int ret;

	ret = kstrtobool(buf, &val);
	if (ret < 0)
	return ret;

	hub->always_powered_in_suspend = val;

	return count;
	}
	static DEVICE_ATTR_RW(always_powered_in_suspend);

	static struct attribute *onboard_hub_attrs[] = {
	&dev_attr_always_powered_in_suspend.attr,
	NULL,
	};
	ATTRIBUTE_GROUPS(onboard_hub);

	static void onboard_hub_attach_usb_driver(struct work_struct *work)
	{
	int err;

	err = driver_attach(&onboard_hub_usbdev_driver.driver);
	if (err)
	pr_err("Failed to attach USB driver: %pe\n", ERR_PTR(err));
	}

	static int onboard_hub_probe(struct platform_device *pdev)
	{
	struct device *dev = &pdev->dev;
	struct onboard_hub *hub;
	unsigned int i;
	int err;

	hub = devm_kzalloc(dev, sizeof(*hub), GFP_KERNEL);
	if (!hub)
	return -ENOMEM;

	hub->pdata = device_get_match_data(&pdev->dev);
	if (!hub->pdata)
	return -EINVAL;

	if (hub->pdata->num_supplies > MAX_SUPPLIES)
	return dev_err_probe(dev, -EINVAL, "max %zu supplies supported!\n",
	MAX_SUPPLIES);

	for (i = 0; i < hub->pdata->num_supplies; i++)
	hub->supplies[i].supply = supply_names[i];

	err = devm_regulator_bulk_get(dev, hub->pdata->num_supplies, hub->supplies);
	if (err) {
	dev_err(dev, "Failed to get regulator supplies: %pe\n", ERR_PTR(err));
	return err;
	}

	hub->clk = devm_clk_get_optional(dev, NULL);
	if (IS_ERR(hub->clk))
	return dev_err_probe(dev, PTR_ERR(hub->clk), "failed to get clock\n");

	hub->reset_gpio = devm_gpiod_get_optional(dev, "reset",
	GPIOD_OUT_HIGH);
	if (IS_ERR(hub->reset_gpio))
	return dev_err_probe(dev, PTR_ERR(hub->reset_gpio), "failed to get reset GPIO\n");

	hub->dev = dev;
	mutex_init(&hub->lock);
	INIT_LIST_HEAD(&hub->udev_list);

	dev_set_drvdata(dev, hub);

	err = onboard_hub_power_on(hub);
	if (err)
	return err;

	/*
	* The USB driver might have been detached from the USB devices by
	* onboard_hub_remove() (e.g. through an 'unbind' by userspace),
	* make sure to re-attach it if needed.
	*
	* This needs to be done deferred to avoid self-deadlocks on systems
	* with nested onboard hubs.
	*/
	schedule_work(&attach_usb_driver_work);

	return 0;
	}

	static void onboard_hub_remove(struct platform_device *pdev)
	{
	struct onboard_hub *hub = dev_get_drvdata(&pdev->dev);
	struct usbdev_node *node;
	struct usb_device *udev;

	hub->going_away = true;

	mutex_lock(&hub->lock);

	/* unbind the USB devices to avoid dangling references to this device */
	while (!list_empty(&hub->udev_list)) {
	node = list_first_entry(&hub->udev_list, struct usbdev_node, list);
	udev = node->udev;

	/*
	* Unbinding the driver will call onboard_hub_remove_usbdev(),
	* which acquires hub->lock. We must release the lock first.
	*/
	get_device(&udev->dev);
	mutex_unlock(&hub->lock);
	device_release_driver(&udev->dev);
	put_device(&udev->dev);
	mutex_lock(&hub->lock);
	}

	mutex_unlock(&hub->lock);

	onboard_hub_power_off(hub);
	}

	MODULE_DEVICE_TABLE(of, onboard_hub_match);

	static const struct dev_pm_ops __maybe_unused onboard_hub_pm_ops = {
	SET_LATE_SYSTEM_SLEEP_PM_OPS(onboard_hub_suspend, onboard_hub_resume)
	};

	static struct platform_driver onboard_hub_driver = {
	.probe = onboard_hub_probe,
	.remove_new = onboard_hub_remove,

	.driver = {
	.name = "onboard-usb-hub",
	.of_match_table = onboard_hub_match,
	.pm = pm_ptr(&onboard_hub_pm_ops),
	.dev_groups = onboard_hub_groups,
	},
	};

	/************************ USB driver ************************/

	#define VENDOR_ID_CYPRESS 0x04b4
	#define VENDOR_ID_GENESYS 0x05e3
	#define VENDOR_ID_MICROCHIP 0x0424
	#define VENDOR_ID_REALTEK 0x0bda
	#define VENDOR_ID_TI 0x0451
	#define VENDOR_ID_VIA 0x2109

	/*
	* Returns the onboard_hub platform device that is associated with the USB
	* device passed as parameter.
	*/
	static struct onboard_hub _find_onboard_hub(struct device dev)
	{
	struct platform_device *pdev;
	struct device_node *np;
	struct onboard_hub *hub;

	pdev = of_find_device_by_node(dev->of_node);
	if (!pdev) {
	np = of_parse_phandle(dev->of_node, "peer-hub", 0);
	if (!np) {
	dev_err(dev, "failed to find device node for peer hub\n");
	return ERR_PTR(-EINVAL);
	}

	pdev = of_find_device_by_node(np);
	of_node_put(np);

	if (!pdev)
	return ERR_PTR(-ENODEV);
	}

	hub = dev_get_drvdata(&pdev->dev);
	put_device(&pdev->dev);

	/*
	* The presence of drvdata ('hub') indicates that the platform driver
	* finished probing. This handles the case where (conceivably) we could
	* be running at the exact same time as the platform driver's probe. If
	* we detect the race we request probe deferral and we'll come back and
	* try again.
	*/
	if (!hub)
	return ERR_PTR(-EPROBE_DEFER);

	return hub;
	}

	static int onboard_hub_usbdev_probe(struct usb_device *udev)
	{
	struct device *dev = &udev->dev;
	struct onboard_hub *hub;
	int err;

	/* ignore supported hubs without device tree node */
	if (!dev->of_node)
	return -ENODEV;

	hub = _find_onboard_hub(dev);
	if (IS_ERR(hub))
	return PTR_ERR(hub);

	dev_set_drvdata(dev, hub);

	err = onboard_hub_add_usbdev(hub, udev);
	if (err)
	return err;

	return 0;
	}

	static void onboard_hub_usbdev_disconnect(struct usb_device *udev)
	{
	struct onboard_hub *hub = dev_get_drvdata(&udev->dev);

	onboard_hub_remove_usbdev(hub, udev);
	}

	static const struct usb_device_id onboard_hub_id_table[] = {
	{ USB_DEVICE(VENDOR_ID_CYPRESS, 0x6504) }, /* CYUSB33{0,1,2}x/CYUSB230x 3.0 */
	{ USB_DEVICE(VENDOR_ID_CYPRESS, 0x6506) }, /* CYUSB33{0,1,2}x/CYUSB230x 2.0 */
	{ USB_DEVICE(VENDOR_ID_CYPRESS, 0x6570) }, /* CY7C6563x 2.0 */
	{ USB_DEVICE(VENDOR_ID_GENESYS, 0x0608) }, /* Genesys Logic GL850G USB 2.0 */
	{ USB_DEVICE(VENDOR_ID_GENESYS, 0x0610) }, /* Genesys Logic GL852G USB 2.0 */
	{ USB_DEVICE(VENDOR_ID_GENESYS, 0x0620) }, /* Genesys Logic GL3523 USB 3.1 */
	{ USB_DEVICE(VENDOR_ID_MICROCHIP, 0x2412) }, /* USB2412 USB 2.0 */
	{ USB_DEVICE(VENDOR_ID_MICROCHIP, 0x2514) }, /* USB2514B USB 2.0 */
	{ USB_DEVICE(VENDOR_ID_MICROCHIP, 0x2517) }, /* USB2517 USB 2.0 */
	{ USB_DEVICE(VENDOR_ID_MICROCHIP, 0x2744) }, /* USB5744 USB 2.0 */
	{ USB_DEVICE(VENDOR_ID_MICROCHIP, 0x5744) }, /* USB5744 USB 3.0 */
	{ USB_DEVICE(VENDOR_ID_REALTEK, 0x0411) }, /* RTS5411 USB 3.1 */
	{ USB_DEVICE(VENDOR_ID_REALTEK, 0x5411) }, /* RTS5411 USB 2.1 */
	{ USB_DEVICE(VENDOR_ID_REALTEK, 0x0414) }, /* RTS5414 USB 3.2 */
	{ USB_DEVICE(VENDOR_ID_REALTEK, 0x5414) }, /* RTS5414 USB 2.1 */
	{ USB_DEVICE(VENDOR_ID_TI, 0x8140) }, /* TI USB8041 3.0 */
	{ USB_DEVICE(VENDOR_ID_TI, 0x8142) }, /* TI USB8041 2.0 */
	{ USB_DEVICE(VENDOR_ID_VIA, 0x0817) }, /* VIA VL817 3.1 */
	{ USB_DEVICE(VENDOR_ID_VIA, 0x2817) }, /* VIA VL817 2.0 */
	{}
	};
	MODULE_DEVICE_TABLE(usb, onboard_hub_id_table);

	static struct usb_device_driver onboard_hub_usbdev_driver = {
	.name = "onboard-usb-hub",
	.probe = onboard_hub_usbdev_probe,
	.disconnect = onboard_hub_usbdev_disconnect,
	.generic_subclass = 1,
	.supports_autosuspend = 1,
	.id_table = onboard_hub_id_table,
	};

	static int __init onboard_hub_init(void)
	{
	int ret;

	ret = usb_register_device_driver(&onboard_hub_usbdev_driver, THIS_MODULE);
	if (ret)
	return ret;

	ret = platform_driver_register(&onboard_hub_driver);
	if (ret)
	usb_deregister_device_driver(&onboard_hub_usbdev_driver);

	return ret;
	}
	module_init(onboard_hub_init);

	static void __exit onboard_hub_exit(void)
	{
	usb_deregister_device_driver(&onboard_hub_usbdev_driver);
	platform_driver_unregister(&onboard_hub_driver);

	cancel_work_sync(&attach_usb_driver_work);
	}
	module_exit(onboard_hub_exit);

	MODULE_AUTHOR("Matthias Kaehlcke <mka@chromium.org>");
	MODULE_DESCRIPTION("Driver for discrete onboard USB hubs");
	MODULE_LICENSE("GPL v2");